1. Field of the Invention
The present invention relates to an image forming apparatus such as a fax machine, a copying machine or a printing machine (including a composite machine made of a combination of two or more of these apparatuses) and, specifically, the present invention relates to an image forming apparatus including a recognition structure for recognizing the compatibility of an image forming process unit which is removably mounted at a given position within a main body of the image forming apparatus.
2. Description of the Related Art
In the above-mentioned image forming apparatus, as an image forming process unit, there is used a developing machine main body unit including a developing machine, a drum unit including a photosensitive drum, expendables such as a toner cartridge for storing toner therein, a replaceable part separately or in the form of a package structured by combining together two or more of these elements. That is, the image forming process unit can be removably mounted at a given position within the main body of the image forming apparatus and, as the need arises, it can be replaced with a new one or a replaceable part that can be recycled.
Recently, from a technological viewpoint such as a resolution viewpoint, or from the viewpoint of uses such as an office use or a domestic use, there have been developed two or more kinds of image forming apparatuses. In conformity with such development, or according to the kinds of the performance of the image forming process unit itself, there have been developed two or more kinds of image forming process units.
In this case, a given kind of image forming apparatus must mount an image forming process unit which corresponds to it. When such image forming apparatus mounts an image forming process unit which does not correspond to it, unfavorably, there is a fear that the image forming apparatus can break or the quality of the image formation thereof can be worsened.
In order to recognize whether an individual image forming process unit corresponds to a given kind of image forming apparatus or not, that is, in order to recognize whether the individual image forming process unit is compatible or not, for example, it can be expected to produce an image forming process unit which is changed in shape according to the kind of an image forming apparatus. However, to produce the image forming process unit while changing the shape thereof according to the kind of image forming apparatus leads to the increased cost of the image forming process unit and thus the image forming apparatus incorporating such an image forming process unit therein.
For example, in JP-A-2001-75455, in order to prevent the unauthorized use of non-genuine parts other than manufacturer's genuine parts as replacement parts such as expendables, there is proposed a replaceable part mounting structure in which, not only, on the butting surface of a toner cartridge where the toner cartridge is butted against a hopper portion provided within the apparatus main body, there is provided a convexo-concave shaped portion having a shape copying or corresponding to the registered logo mark of a company which others are prohibited from using, but also, on the hopper portion, there is provided a concavo-convex shaped portion corresponding in shape to the above-mentioned convexo-concave shaped portion, whereby the hopper portion and toner cartridge can be positioned through the concavo-convex engagement between these convexo-concave and concavo-convex shaped portions.
According to the mounting structure disclosed in JP-A-2001-75455, when the apparatus main body and toner cartridge are one to one, the compatibility can be recognized effectively. However, to recognize the compatibility of two or more kinds of image forming process units as described above with the image forming apparatus, the shape of the toner cartridge or the shapes of the convexo-concave and concavo-convex shaped portions must be changed according to the kinds of the image forming process units, which is not preferred from the viewpoint of the cost of the image forming apparatus.
According to JP-A-2005-301077, there is proposed a developing machine in which, at a position near the mounting-direction rear end of the upper surface of a developing machine which can be mounted onto the main body of an image forming apparatus, there are arranged two or more rectangular frame-shaped mounting portions perpendicularly to the mounting direction; a given number of recognition projecting portions for recognizing the compatibility of the developing machine with the apparatus main body are fitted at given positions and fixed there in the mounting portions; in the lower surface of the opening of the apparatus main body where the developing machine can be mounted, specifically, in the positions thereof that correspond to the mounting portions, there are formed recessed portions onto which two or more recognition engaging portions can be mounted; and, the recognition engaging portions are fixed to the recessed portions that do not correspond to the recognition projecting portions fixed to the mounting portions, thereby being able to recognize the compatibility of the developing machine with the apparatus main body. That is, when a developing machine that is incompatible with the apparatus main body is inserted into the image forming apparatus, the recognition projecting portions and recognition engaging portions collide with each other to thereby prevent the developing machine from being inserted into the apparatus main body, which can secure compatibility between the apparatus main body and developing machine.
According to the developing machine, by changing the fixing number and position of the recognition projecting portions and recognition engaging portions, there are possible two or more sets of combinations for recognition of compatibility, whereby the developing machine can be applied according to the kinds of the combination sets without changing the shapes of image forming apparatus and image forming process units themselves.
However, according to the developing machine proposed in JP-A-2005-301077, since the mounting portions must be provided on the upper surface of the developing machine which is limited in space, the number of combination sets for compatibility recognition is also limited and also, between the upper surface of the developing machine and the lower surface of the opening of the apparatus main body, there must be secured a space for the recognition projecting portions and recognition engaging portions, especially, it is necessary to provide a space extending in the height direction of the apparatus main body. This obstructs the formation of a compact structure for the apparatus main body.